Mitchell Valdés-Sosa

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Event-related potentials (ERPs) and behavioral data were recorded while subjects performed two tasks on the same set of faces (presented in pairs). One task was identity matching and the other expression matching. Two groups of subjects participated, one familiar and the other unfamiliar with the faces. Subjects were less accurate in matching expressions(More)
Rightward shifts in attention are a common consequence of brain injury. A growing body of evidence appears to suggest that increases in attentional load, and decreases in alertness can lead to rightward shifts in attention in healthy and patient populations. It is unclear however whether these factors affect spatial biases in attention at the level of(More)
The association of enumeration and number comparison capacities with arithmetical competence was examined in a large sample of children from 2nd to 9th grades. It was found that efficiency on numerical capacities predicted separately more than 25% of the variance in the individual differences on a timed arithmetical test, and this occurred for both younger(More)
Patients with prosopagnosia are unable to recognize faces consciously, but when tested indirectly they can reveal residual identification abilities. The neural circuitry underlying this covert recognition is still unknown. One candidate for this function is the partial survival of a pathway linking the fusiform face area (FFA) and anterior-inferior temporal(More)
Objects frequently have a hierarchical organization (tree-branch-leaf). How do we select the level to be attended? This has been explored with compound letters: a global letter built from local letters. One explanation, backed by much empirical support, is that attentional competition is biased toward certain spatial frequency (SF) bands across all(More)
Attending to objects implies the concurrent process of features that are analyzed in different visual subsystems or domains. Previous works have shown that attention cannot be simultaneously directed to the components of motion present in two transparent surfaces [M. Valdés et al., Cognition 66 (1998) B13-B23], even though they occupy overlapping regions of(More)
During transparent motion, attention to changes in the direction of one illusory surface will impede recognition of a similar event affecting the other surface if both are close together in time. This is a form of object-based attentional blink (AB). Here, we show that this AB is related to a smaller N200 response to the change in direction and that the(More)
Expectancies about face-structure can be induced by viewing parts of faces, which generates constraints due to two types of knowledge: feature-content and configuration. In a first experiment ERPs were recorded when parts of familiar faces were completed with incongruent features (from another face), as opposed to congruent features (from the same face).(More)
In this study, we explored the influence of an irrelevant translational event on the automatic capture of attention to one of two superimposed surfaces defined by transparent motion. The results showed that an irrelevant translation on one surface did not automatically capture the subjects' attention if the attentional resources have been endogenously(More)
Familiar faces convey different types of information, unlocking memories related to social-emotional significance. Here, the availability over time of different types of memory was evaluated using the time-course of P3 event related potentials. Two oddball paradigms were employed, both using unfamiliar faces as standards. The infrequent targets were,(More)